Pompe disease is an autosomal recessive disease, enzyme replacement therapy (ERT) and new born screen (NBS) had been initiated in Taiwan since 2008. However, residual muscle weakness were noted. Decrease in amplitude of nerve compound muscle action potential (CMAP) and increase spontaneous activity were reported before the imitation of ERT. However, the motor development, motor function and electrodiagnostic presentation which were important in further direction of treatment and rehabilitation program arrangement in infantile Pompe disease (IOPD) under ERT is lacking.